In the field of espresso coffee machines and the like, infusion devices are known which work with infusion capsules and the like and are constituted substantially by a main frame with which a filter basket holder cylinder and a piston are associated.
More precisely, the filter basket holder cylinder and the piston, which can move with respect to each other along a preferred direction, define a receptacle in which the capsule containing the substances through which hot or cold water is to be filtered, thus producing the desired infusion, is inserted.
Generally, the capsule consists of a hermetically closed container which is pierced, typically on two opposite faces, so as to allow the hot or cold water to filter through it, or it consists of a container with entry and exit holes provided on the two opposite faces, so as to allow the hot or cold water to filter through its interior.
In the case of capsules requiring piercing, the filter basket holder cylinder and the feeding piston in fact have hollow piercing tips, which protrude within the receptacle and in the direction of the capsule and are connected to the ducts for delivery of the hot or cold water and the discharge ducts of the infusion device for the outflow of the infusion.
In practice, once the capsule has been inserted in the corresponding receptacle, its piercing occurs by moving the filter basket holder and the piston closer together and mutual clamping of the filter basket holder cylinder and the piston, so that the piercing tips are pushed into the capsule. This piercing is made possible thanks to the presence of adapted lever systems, which are functionally connected to the filter basket holder cylinder or to the piston or to both and can be actuated manually by the operator by means of an actuation lever that can be gripped by the operator.
As an alternative, the actuation lever can be replaced by motor means, for example of the electrical type, so as to facilitate and automate the relative movement between the filter basket holder cylinder and the piston.
More precisely, the lever system, regardless of whether it is operated manually or automatically, moves the two elements, the filter basket holder cylinder and the piston, closer together with a single movement and in theory transmits the thrust required for piercing.
Likewise, these movements can also occur in infusion devices that do not provide for piercings of the capsule that contains the substances through which hot or cold water is to filter, thus producing the desired infusion, since they are already provided with the water passage holes.
These known types of infusion devices are not devoid of drawbacks, which include the fact that the thrust provided by the operator can entail an effort which is inconvenient to said operator both when using capsules to be pierced and when using capsules not to be pierced.
Moreover, if capsules to be pierced are used, the material of which such capsules are made has a resistance to piercing that requires a mutual thrust between the filter basket holder cylinder and the piston that is much greater than the thrust required to achieve the simple mutual approach of the filter basket holder cylinder and the feeding piston.